Switch cabinet arrangement with at least one it rack or switch cabinet housing and with at least one cooling unit, and a corresponding method

ABSTRACT

The invention relates to a switch cabinet arrangement with at least one IT rack or switch cabinet housing and with at least one cooling device, which has an air-liquid heat exchanger for cooling components accommodated in the IT rack or switch cabinet housing with cooled air, wherein the air-liquid heat exchanger comprises a first flow for cooled liquid and a first return for heated liquid, wherein the cooling device comprises a liquid-liquid heat exchanger, to the second flow of which the first return of the air-liquid heat exchanger is connected. A corresponding method is further described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase application under 35 U.S.C.371 of International Application No. PCT/DE2020/100821, filed on Sep.23, 2020, which claims the benefit of German Patent Application No. 102019 125 521.0, filed on Sep. 23, 2019, German Patent Application No. 102019 125 534.1, filed on Sep. 23, 2019, German Patent Application No. 102020 105 359.2, filed on Feb. 28, 2020, and International ApplicationNo. PCT/DE2020/100704, filed on Aug. 13, 2020. The entire disclosures ofthe above applications are incorporated herein by reference.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

TECHNICAL FIELD

The invention is based on a switch cabinet arrangement with at least oneIT rack or switch cabinet housing and with at least one cooling device,which has an air-liquid heat exchanger for cooling componentsaccommodated in the IT rack or switch cabinet housing with cooled air,the air-liquid heat exchanger having a first flow for cooled liquid anda first return for heated liquid. Such a switch cabinet arrangement isknown, for example, from DE 10 2015 101 022 B3.

DISCUSSION

The components arranged in a switch cabinet housing or in an IT rackgenerally have a high power loss depending on the design and a coolingpower requirement that varies accordingly from component to component.On the other hand, the cooling power in common Switch cabinetarrangements is provided independently of the component with cooling airof the same temperature, which flows around the components requiringcooling. Consequently, the cooling air temperature and its flow velocityare always adjusted so that sufficient cooling power can be provided forthe components with the highest cooling power requirement. Conversely,however, this has the consequence that components requiring less coolingare excessively cooled, making the overall cooling concept of the switchcabinet arrangement energy inefficient.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

It is therefore one aspect of the invention to further develop a switchcabinet arrangement of the type described at the beginning in such a waythat energy-efficient cooling of components with different cooling powerrequirements of the same switch cabinet arrangement is possible.

Accordingly, it is provided that the cooling device comprises aliquid-liquid heat exchanger, to the second flow of which the firstreturn of the air-liquid heat exchanger is connected.

The idea of the invention is thus based on providing, in addition to thestandard air-liquid heat transfer, a second heat transfer between twoliquids by means of an additional liquid-liquid heat exchanger. Due tothe improved thermal conductivity of liquids compared to air, it is thuspossible to provide a cooling liquid for cooling components that requirea comparatively high cooling capacity. Furthermore, the improved thermalconductivity of the liquid compared to air allows the supply temperatureof the liquid for liquid cooling of the components to be selected to behigher compared to the temperature of the cooling air, and therefore theheated liquid flowing out of the return of the air-liquid heat exchangermay still be sufficient to provide sufficient cooling of the secondliquid for direct cooling of the components when fed into the supply ofthe liquid-liquid heat exchanger. The switch cabinet arrangementaccording to the invention therefore allows cooling at at least twodifferent temperature levels, namely once at the temperature level ofthe cooled air flowing out of the air-liquid heat exchanger and once atthe temperature level of the cooled liquid provided by the liquid-liquidheat exchanger, wherein the cooled liquid provided by the liquid-liquidheat exchanger may be substantially warmer than the cooling air, forexample at least 20 K warmer.

The principle according to the invention can be scaled as desired.Instead of one liquid-liquid heat exchanger, several liquid-liquid heatexchangers can be fed by the return flow of the air-liquid heatexchanger. By suitable selection of the second liquid which serves fordirect cooling of the components, by suitable selection of the flow rateof the respective liquid through the liquid-liquid heat exchanger and,if necessary, the additional variation of operating parameters, thetemperature of the respective second liquid provided can be adjusted, sothat a switch cabinet arrangement according to the principles of theinvention can be provided with a plurality of different cooling liquidflow temperatures for direct cooling of components requiring differentcooling power requirements.

The air-liquid heat exchanger can be part of a first cooling circuit andthe liquid-liquid heat exchanger can be part of a second cooling circuitseparate from the first. The first and/or the second cooling circuit maycomprise at least one coolant, or a refrigerant, or another coolingmedium, which is at least partially liquid and circulated in therespective circuit. The two cooling media may differ in particular withrespect to their condensation temperature at which they change from anat least partially gaseous phase to a liquid phase.

The liquid passing through the air-liquid heat exchanger may be water ora liquid containing mostly water.

A first of the two liquids passed through the liquid-liquid heatexchanger may have a boiling point under standard conditions that isbelow the boiling point of the second liquid passed through theliquid-liquid heat exchanger, preferably at least 20 K, more preferablyat least 30 K, and most preferably at least 40 K below the boiling pointof the second liquid.

The second of the two liquids passed through the liquid-liquid heatexchanger may be or comprise a perfluorinated chemical compound,preferably a compound derived from ethyl isopropyl ketone, particularlypreferably perfluoro(2-methyl-3-pentanone), C₆F₁₂O.

The second of the two liquids passed through the liquid-liquid heatexchanger may be introduced from a third return of the liquid-liquidheat exchanger into a liquid-carrying heat conducting body forconduction cooling.

The second of the two liquids passed through the liquid-liquid heatexchanger may have been introduced from the liquid-carrying heattransfer body into a third flow of the liquid-liquid heat exchanger.

The liquid-liquid heat exchanger may be the cooling zone of a heat pipeor a distribution pipe. The liquid-liquid heat exchanger can be formedin one piece or from several liquid-liquid heat exchangers fluidicallyconnected in series or in parallel.

The heat pipe or the distribution pipe can have a downpipe and a riserpipe, which are designed as fluidically separated vertical lines or arefluidically connected to each other in a lowermost region of the heatpipe or distribution pipe via a siphon and/or a coolant collecting tank.The liquid coolant can be fed from the coolant reservoir via a pump intoa flow line of a heat conducting body for conduction cooling of asemiconductor component.

The heat pipe or manifold may include a down pipe into which secondliquid cooled from the liquid-liquid heat exchanger is introduced.

The heat pipe or manifold may include a riser pipe into which heatedsecond liquid is introduced.

From a recooler, such as a chiller, chilled liquid may be introducedinto the air-liquid heat exchanger via the first chilled liquid supplyline.

The cooled liquid may be introduced into the recooler as a heated liquidfrom the liquid-liquid heat exchanger.

The cooling unit may be a cooling unit lined up in a row of IT racks orenclosures, with hot air drawn in from a hot aisle through the back orfront of the unit and blown out as cooled air into a cold aisle throughthe side opposite the back or front.

The cooling unit may be housed within the enclosure and have a sidecooling air outlet and a hot air inlet open to the same side, with aplurality of heat-emitting components disposed between them. Within theenclosure, cooling air exiting the cooling air outlet may be introducedpast or through the components as heated air into the warm air inlet.

The air-liquid heat exchanger of the first circuit and the liquid-liquidheat exchanger of the second circuit can be arranged in a single-walledor double-walled rear door or front door of the IT rack or the switchcabinet housing. Air can flow through the air-liquid heat exchanger andthe liquid-liquid heat exchanger, which enters the IT rack or the switchcabinet housing on a side arranged opposite the rear door or the frontdoor. At least one fan and preferably a plurality of fans may beprovided for air transport.

In accordance with another aspect of the invention, there is provided aswitch cabinet arrangement having at least one IT rack or enclosurehousing, wherein air is passed through the IT rack or switch cabinethousing for cooling components received in the IT rack or enclosurehousing. In this case, a second air-liquid heat exchanger of a secondcooling circuit is charged by the air, and a liquid passed through theair-liquid heat exchanger is supplied to at least one of the componentsfor heat transfer from the component to the liquid and is dischargedfrom the component back into the air-liquid heat exchanger.

The air can be introduced from outside the switch cabinet arrangementpartly into the at least one IT rack or the switch cabinet housing andpartly into a cooling unit housing, which is associated with the IT rackor the switch cabinet housing and fluidically separated therefrom and inwhich the air-liquid heat exchanger is accommodated. For this purpose,the air-liquid heat exchanger can be arranged in a cooling unit housingwhich is associated with the IT rack or the switch cabinet housing.Furthermore, an air-liquid heat exchanger of a further refrigerantcircuit may be arranged in the cooling device housing, for example awater circuit, in which cooled water is provided via a recooler, forexample a chiller, for the provision of cooled air by means of thefurther air-liquid heat exchanger. The one of the two air-liquid heatexchangers via which the cooled liquid is provided for direct cooling ofthe components may be arranged in the air flow passing through theenclosure downstream of the air-liquid heat exchanger providing cooledair for air cooling of the components. In particular, in the mannerdescribed above, the liquid direct cooling of the components may beimplemented using a refrigerant that has a higher boiling point comparedto the air that is commonly used for air cooling of components in, forexample, an IT environment. For example, the cooled air that impinges onthe components may have a temperature that is 25° C., while the boilingpoint of the refrigerant is greater than 50° C.

The air may be introduced into the at least one IT rack or the switchcabinet housing from outside the Switch cabinet arrangement, the Switchcabinet arrangement having an air duct in which the air acts on thecomponents in its direction of flow after entering the IT rack or theswitch cabinet housing before it acts on the air-liquid heat exchangeras air partially heated by the components. As previously described, dueto the comparatively high boiling point of the refrigerant for componentliquid cooling, air that has already been preheated after passingthrough the components can still be used to condense the refrigerant.For example, the cooling air may have a temperature of 25° C. when itenters the IT rack or cabinet enclosure. After passing through thecomponents, it may have a temperature of 35° C. After passing theair-liquid heat exchanger, the air may have a temperature of more than50° C.

The air-liquid heat exchanger of the second circuit can be arranged in asingle-walled or double-walled rear door or front door of the IT rack orthe switch cabinet housing, with air flowing through the air-liquid heatexchanger and entering the IT rack or the switch cabinet housing on aside arranged opposite the rear door or the front door.

The IT rack or cabinet enclosure may have an air flow path in which theair in its direction of flow after entering the IT rack or cabinetenclosure impacts the components before entering the rear door or frontdoor as air partially heated by the components and impacting theair-liquid heat exchanger of the second circuit.

The second air-liquid heat exchanger may have a housing with an annulargap formed between an outer wall and a tubular inner wall, through whichthe liquid is passed in thermal contact with at least the inner wall. Inthis case, the inner wall can enclose a fan, which is arranged to guidethe air past the inner wall through the housing.

A method for air conditioning a switch cabinet arrangement may includethe steps of:

-   -   Exposing components housed in an IT rack or a cabinet enclosure        of the cabinet assembly to air, wherein the air is heated to a        first temperature, and    -   Passing the air heated to the first temperature through an        air-liquid heat exchanger, cooling a liquid of a liquid cooling        the components and heating the air to a second temperature        greater than the first temperature.

In this case, after passing through the heat exchanger at the secondtemperature, the air can be discharged into the environment of theswitch cabinet arrangement or cooled by another heat exchanger andrecirculated for re-impingement of the components with air.

After passing through the heat exchanger, the air at the secondtemperature can be conducted away from the switch cabinet arrangementvia a chimney. The chimney can open into a further air-liquid heatexchanger, for example into a further air-liquid heat exchanger to whicha cooled liquid cooling medium is supplied via a chiller.

An alternative method for air conditioning a switch cabinet arrangementmay include the steps of:

-   -   Charging components housed in an IT rack or a switch cabinet        housing of the switch cabinet arrangement with air, whereby the        air is heated,    -   Passing the heated air through an air-liquid heat exchanger,        cooling the air and heating a first liquid passed through the        air-liquid heat exchanger,    -   Passing the heated first liquid through a liquid-liquid heat        exchanger, wherein a second liquid passed through the        liquid-liquid heat exchanger of a liquid cooling the components        is cooled and the first heated liquid is further heated.

The first further heated liquid can be discharged from the liquid-liquidheat exchanger, cooled outside the switch cabinet arrangement, andrecirculated as a cooled liquid into the air-liquid heat exchanger.

For the heat transfer from the component to be cooled to a coolant,which can be designed in particular as a cooling liquid, a coolingarrangement can be provided for the direct cooling of the components,for example a cooling arrangement for the direct cooling ofsemiconductor components, such as CPUs. The arrangement may comprise atleast one heat conducting body having a cavity, through which a coolantflows and which is arranged to contact a semiconductor component withits underside in a thermally conductive manner. The heat conducting bodycan have a coolant inlet opening into the cavity and a coolant returnopening into the cavity. The coolant inlet can advantageously bearranged above the coolant return.

The coolant inlet can have an adjustable closing element with which avertical opening cross section of the coolant inlet can be adjusted. Theclosing element can have a slide valve which is linearly adjustable, theslide valve preferably being adjustable in the vertical direction andopening the opening cross section in a lowest position and at leastpartially closing it in an uppermost position.

The coolant inlet can be supplied with coolant via a coolant pump. Thepump can supply the coolant as liquid coolant from a coolant reservoirand via a coolant supply line to the coolant inlet.

A plurality of the heat conducting bodies can be fluidically connectedin parallel in that the heat conducting bodies are connected to the samecoolant supply line via their respective coolant inlet. The at least oneheat conducting body can be connected via its coolant return to acondensation zone, in which coolant exiting via the coolant return andat least partially evaporated is cooled. The condensation zone may havea liquid-liquid heat exchanger through which the coolant passed throughthe at least one heat conducting body is passed along a first coolantcircuit. A liquid passed through a second coolant circuit of theliquid-liquid heat exchanger may be water or a liquid comprising mostlywater. The coolant passed through the at least one heat conducting bodymay have a boiling point under standard conditions that is below theboiling point of the liquid passed through a second coolant circuit ofthe liquid-liquid heat exchanger, preferably at least 20 K, morepreferably at least 30 K, and most preferably at least 40 K below theboiling point of the liquid.

The condensation zone, into which the at least one coolant return lineopens, can have a gradient, with a coolant collection tank, from whichthe coolant is fed to the coolant inlet via a coolant supply line, beingarranged below all the heat conducting bodies.

The coolant may be or comprise a perfluorinated chemical compound,preferably a compound derived from ethyl isopropyl ketone, particularlypreferably perfluoro(2-methyl-3-pentanone), C₆F₁₂O.

The coolant return may have a vertical opening cross-section larger thana maximum opening cross-section of the coolant inlet.

The coolant return can be pressure-free so that the coolant can drainoff unhindered via the coolant return.

The coolant return can be arranged at a distance from a lower boundarywall of the cavity, wherein a filling level of the coolant in the cavityabove the lower boundary wall is predetermined by the distance, andwherein an evaporation volume of the cavity is determined by a furtherdistance of the coolant return from an upper boundary wall arrangedopposite the lower boundary wall.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

Further details of the invention are explained with reference to thefigures below. These show only exemplary embodiments which are notintended to limit the invention. Thereby shows:

FIG. 1 a switch cabinet arrangement according to the state of the art;

FIG. 2 an exemplary embodiment of a switch cabinet arrangement accordingto the invention;

FIG. 3 a further embodiment of a switch cabinet arrangement according tothe invention;

FIG. 4a-4c three exemplary embodiments of a switch cabinet arrangementaccording to the invention with different relative arrangement of thecooling unit to the switch cabinet housing;

FIG. 5 schematically, different variants of the interconnection of anair-liquid heat exchanger with a liquid-liquid heat exchanger;

FIG. 6 schematically, the heat transfer between a component to be cooledand a heat conducting body according to a first embodiment;

FIG. 7 schematically, the heat transfer between a component to be cooledand a heat conducting body according to a second embodiment;

FIG. 8 schematically, the heat transfer between a component to be cooledand a heat conducting body according to a third embodiment;

FIG. 9 in schematic representation, a further embodiment of the switchcabinet arrangement according to the invention;

FIG. 10 in schematic representation, a further embodiment of a switchcabinet arrangement according to the invention;

FIG. 11 in schematic representation, an exemplary embodiment of amanifold;

FIG. 12 in schematic representation, further embodiments of a manifold;

FIG. 13 in schematic representation, another embodiment of a manifold;

FIG. 14 in schematic representation, a further embodiment of a manifold;

FIG. 15 in schematic representation, a further embodiment of a manifold;

FIG. 16 in schematic representation, a further embodiment of a manifold;

FIG. 17 an exemplary embodiment of a liquid-liquid heat exchanger inperspective,

FIG. 18 a perspective view of the heat exchanger according to FIG. 17looking at the sectional plane C;

FIG. 19 the heat exchanger according to FIG. 17 with a view of thesectional plane B; and

FIG. 20 the heat exchanger according to FIG. 17 with a view of thesectional plane A.

FIG. 21 in schematic illustration, the fluid flows of the embodimentaccording to FIG. 3;

FIG. 22 another embodiment of a switch cabinet arrangement according tothe invention;

FIG. 23 in schematic representation, an illustration of the fluid flowsof the embodiment according to FIG. 23;

FIG. 24 another embodiment of a switch cabinet arrangement according tothe invention;

FIG. 25 in schematic representation, an illustration of the fluid flowsof the embodiment according to FIG. 24;

FIG. 26 a further embodiment of a switch cabinet arrangement accordingto the invention; and

FIG. 27 in schematic representation, an illustration of the fluid flowsof the embodiment according to FIG. 26.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

FIG. 1 shows a switch cabinet arrangement according to the state of theart. A first cooled liquid, in this case water, is provided via arecooler 15 arranged outside a building, for example a data center,which can be designed, for example, as a chiller, and is made availableto a cooling unit 2 arranged in the data center. The cooling unit 2 hasan air-liquid heat exchanger 3, via which cooling air is provided, whichis blown into a raised floor of the data center. From the raised floor,the cooling air is blown in front of the enclosures or IT racks 1 sothat the cooling air can be drawn in by components arranged therein, forexample server racks. Alternatively or additionally, the switch cabinets1 can form a row of switch cabinets separating a hot aisle from a coldaisle of the data center, whereby a cold air overpressure is provided inthe cold aisle via fans arranged in the raised floors, which transportsthe cooling air through the cabinets 1 into the hot aisle as heated airand thereby cools the components arranged in the cabinets 1.

In addition to the air cooling, liquid cooling is provided, for exampleCPU liquid cooling, for which purpose a further recooler 15 is providedwhich liquefies a refrigerant which may, for example, have a boilingtemperature which may be close to a preferred operating temperature ofcomponents requiring cooling. Thus, when the refrigerant is supplied tothe components requiring cooling, the power dissipation generated bythem can lead to evaporation of the refrigerant so that, due to thephase transition from liquid to gas, there is a particularly high heattransfer from the component to the refrigerant and thus effectivecooling. The heat transfer from the refrigerant to the components ispromoted by means of heat conducting bodies 10, which are in directcontact with the component to be cooled. The heat conducting bodies 10can essentially consist of a material with very good thermalconductivity, for example a metal, which forms a heat conducting bodythrough which the refrigerant is passed and which, if necessary,undergoes the phase transition from liquid to gaseous described abovewithin the heat conducting body 10, the refrigerant preferably beingprovided at a flow rate or with a flow volume and a temperature whichare selected in such a way that only a partial quantity of therefrigerant volume flow passed through evaporates and a further partremains liquid, so that the evaporated part can be transported out bythe liquid part of the refrigerant flowing in order to be liquefiedagain in the recooler 15.

In contrast, FIGS. 3 to 5 show exemplary embodiments of a switch cabinetarrangement according to the invention. In this arrangement, a firstcooled liquid, for example water, is supplied to the cooling unit 2 viaa first flow 5, with which liquid flowing through the heat exchanger 3.For this purpose, the heat exchanger 3 has a first return 6, which now,in deviation from the solution according to FIG. 1, does not opendirectly into the recooler 15, but is connected to a supply 8 of aliquid-liquid heat exchanger 7. The heat exchanger 7 has a second return16, which is fed to a recooler 15 analogously to the embodimentaccording to FIG. 1. Via the liquid-liquid heat exchanger 7, a heattransfer takes place between the liquid circuit of the air-liquid heatexchanger and a second refrigerant circuit fluidically separatedtherefrom, which may, for example, have a refrigerant with a differentboiling point, as has already been described with reference to FIG. 1.Since the second refrigerant circuit can be operated at a temperaturelevel which is above that of the first refrigerant circuit with theair-liquid heat exchanger 3, the heated liquid provided via the firstreturn 6 can serve as a cooling liquid which is introduced into theliquid-liquid heat exchanger 7.

FIGS. 4a to 4c show three different relative arrangements of a coolingunit housing 2 with respect to a switch cabinet housing 1. The differingrelative arrangement of the two components 1, 2 with respect to oneanother results in a different air flow. In particular, therefore,according to the invention, both embodiments are conceivable in whichthe air cooled via the air-refrigerant heat exchanger 3 and flowing overthe components 4 requiring cooling merely circulates between the coolingdevice and the switch cabinet housing, i.e. fluidically separated fromthe environment of the switch cabinet arrangement, forming a closed aircircuit. On the other hand, there are arrangements in whichfundamentally different air flows flow through the switch cabinethousing 1 on the one hand and the cooling unit 2 on the other, wherebythese arrangements are used in particular in so-called cold aisle-hotaisle constellations in data centers and the like.

In detail, FIG. 4 a shows an arrangement in which the air circulatesexclusively between the directly adjacent and fluidically interconnectedhousings of cooling unit 2 and switch cabinet 1. The air cooled via theair-refrigerant heat exchanger 3 is drawn through the heat exchanger 3by a fan 19 and forced into the switch cabinet housing 1, for whichpurpose it is blown laterally into the switch cabinet housing 1 at arear side of the switch cabinet housing 1. The cooling air flows throughthe switch cabinet housing 1 in a substantially horizontal direction,flowing around the components 10 requiring cooling, whereupon it entersthe cooling unit 2 at the front of the switch cabinet housing 1 asheated air again via a lateral, fluidic air transition in order to flowthrough the air-refrigerant heat exchanger 3 again.

In the manner already described, the refrigerant return of theair-refrigerant heat exchanger 3 is connected to a flow 8 of therefrigerant-refrigerant heat exchanger 7, whereby the refrigerantleaving the air-refrigerant heat exchanger 3 as partially heatedrefrigerant KM1 after passing the liquid-liquid heat exchanger 7 leavesthe latter via the return 16 in order to be recooled, for example, viaan external recooler (compare FIG. 2). The refrigerant KM1 can be water,for example.

In contrast to the embodiment shown in FIG. 4a , in the embodiment shownin FIG. 4b no air-fluid transition is provided between the housings ofswitch cabinet 1 and cooling unit 2, with ambient air flowing throughboth housings in an antiparallel manner. The ambient air can be, forexample, the air which is received in a cold aisle hot aisle arrangementbetween the rows of switch cabinets. For example, the switch cabinethousing can discharge the cold air drawn in via the rear side as heatedair via its front side in the manner known from the prior art. In thearrangement according to the invention as shown in FIG. 4b , it can nowbe provided that the warm air from the warm aisle enters the coolingunit via the front of the cooling unit housing 2, where it passes theliquid-air heat exchanger 3 and enters the cold aisle at the rear of thearrangement as cooled air. The cooled air in the cold aisle mayrepeatedly enter the enclosure through the rear of the enclosure to flowover the components 4 requiring cooling.

The embodiment according to the embodiment according to FIG. 4c differsfrom the embodiment according to FIG. 4b in that the housings of coolingunit 2 and switch cabinet 1 have an offset in the horizontal direction,whereby the cooled air exiting laterally at the rear of cooling unithousing 2 enters switch cabinet 1 via the rear. In the manner alreadydescribed, the cooled air flows over the components 4 requiring coolingand is heated in the process. At the front of the switch cabinethousing, the heated air again exits laterally from the switch cabinet 1to be blown directly in front of the front of the cooling unit housing2, where it can again be drawn into the housing 2 via the fan 19 andtransported through the air-refrigerant heat exchanger 3 to then blowthe air out again as cooled air laterally at the rear of the coolingunit housing 2 directly in front of the rear of the switch cabinethousing 1.

In the further FIGS. 5 to 20, the cooling of heat-emitting electricallyoperated components in an essentially closed enclosure is shown as anexample, wherein the medium G1 is cooled by component A1 with an air orgas cooler WÜ1, with the cooling medium KM1, and G1 mainly flows backand forth between cooling and electrically operated objects located inthe enclosure. G1 is thereby cooled in a device or component (A1)located adjacent to the enclosure and/or in the enclosure and/orconnected to the enclosure by substantially closed channels (sheet metalchannels, hoses or also brushes). A1 can be used to cool one or moreenclosures such as IT racks or switch cabinet enclosures.

KM1 may consist of a solid or liquid or gaseous or multiphase orphase-changing coolant material of one or more substances. KM1 canpreferably be water or water with additives or a refrigerant with areduced condensation temperature compared to water.

In addition to cooling G1, further cooling of a second cooling mediumKM2 is performed by component A1. KM2 may consist of a solid or liquidor gaseous or multiphase or phase-changing cooling substantiallydielectric material of one or more substances. This may preferably be1,1,1,2,2,4,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone or1,1,1,2,3,3-heptafluoro-3-methoxypropane with various possible degreesof purity (high purity or impure).

Cooling of KM2 takes place through KM1 by means of a heat exchanger WÜ2,with or without mixing of KM1 and KM2. KM1 can first cool components ordevice G1 and then cool medium KM2 or vice versa or in parallel.

In a further embodiment, G1 or KM2 may also be cooled in a separatecircuit by a cooling medium KM3. KM3 may comprise a solid or liquid orgaseous or multiphase or phase-changing cool substantially dielectricmaterial of one or more substances. KM3 may preferably be water or waterwith additives or refrigerant.

KM2 is then provided as again cooling material for at least oneelectrically operated device or such a component which can become evenwarmer than KM2 (in particular semiconductor elements, such as CPUs) bymeans of a suitable channel, in particular at least one tube and/orhose.

In this case, the at least one electrically operated device or componentto be cooled is located in an enclosure and is cooled with KM2, wherebyother electrically operated devices or components can be located in thesame or another enclosure, which are cooled with G1.

The cooling medium is provided in particular by hydraulicallycommunicating tubes, a wire mesh or a pump, in particular anelectrically or pneumatically driven pump or a thermally driven bladderpump or a combination thereof. Here, in particular embodiments, thecooling temperature of KM2 is matched to the maximum allowable oreconomically optimal cooling temperature of the component to be cooled.In particular, the cooling temperature can be adjusted by changing thepressure to change the condensation temperature or by selecting the KM2cooling medium.

The cooling medium KM2 is heated or not heated by the at least oneobject to be cooled. The phase of KM2 is wholly or partially changed (inparticular wholly or partially evaporated), discharged again through thesame channel or one or more other channels. If the component is notgiving off heat, the provision of KM2 may be stopped in whole or in partby a control of some kind, or it may continue. KM2 may be running in theduct, stationary, or the duct may be idle. The supply of KM2 may beunregulated and in such a way that KM2 always runs through the coolerand evaporates or drains over an overflow edge.

A well thermally conductive hollow body is mounted on the semiconductorcomponent, which is filled with an electrically non-conductive liquidwith a suitable evaporation temperature. To ensure that there is alwaysa sufficient liquid level above the chip area intended for heatdissipation, the hollow body can be designed as follows:

The hollow body has an inlet and an outlet, whereby the outlet isdesigned in such a way that a volume not filled with coolant remainsabove the outlet opening during normal operation. For this purpose, theinlet is limited by a suitable orifice in the line in such a way thatmore coolant always enters the hollow body than can evaporate at maximumheat input. The outlet, on the other hand, is designed so large thatmore coolant can always escape in both liquid and gaseous phases than isintroduced through the inlet.

The inlet and outlet of the heat conducting body are designed in such away that there is always a vertical gradient to ensure that evaporationin the hollow body is not hindered by coolant backing up in the outlet.

The invention is primarily for indirect or direct cooling ofheat-emitting components in enclosures, in particular of one or moreservers (especially in clusters of servers), such that some componentsthereof are cooled by a corresponding KM2 and other components(especially those having higher temperature resistance) are cooled bythe cooled G1, whereby the G1 can be used with a higher inlettemperature than previously necessary due to this separation of thecooling systems, in particular to achieve a higher inlet and outlettemperature of KM1.

In a further variant is used for indirect or direct cooling of heatemitting objects in enclosures, in particular of one or more servers(especially in collections of servers, so that some components arecooled by a corresponding KM2 and other components are cooled by thecooled air, whereby the air, by this separation of the cooling systems,can be used with a higher inlet temperature than previously usual or apreviously usual inlet temperature, in particular to achieve a higheroutlet temperature of KM1.

A further variant is used for indirect or direct cooling ofheat-emitting objects in enclosures, in particular of one or moreservers (especially in collections of servers), so that some componentsare cooled by a corresponding KM2 and other components are cooled by thecooled air, whereby the air can be used in this separation with a higherinlet temperature than previously usual or a previously usual inlettemperature, in particular in order to achieve a particularly high heattransfer performance of the cooling by means of a high temperaturedifference between the condensation temperature of KM 2 and previouslyusual cold KM1 and thus to achieve a particularly high coolingperformance per semiconductor element or per component A1 or to reducethe volume of the components A1.

The solutions described offer new possibilities due to their type ofcooling, in particular for increasing the heat flux density selectivelywhere it may become necessary or for miniaturizing heat-emittingobjects. For other heat-emitting objects, the invention enables aselective increase of the cooling temperature in order to save costs orto be able to release the energy absorbed in KM1 more easily to theenvironment at a higher temperature level or to be able to use itfurther, in particular for heating and/or drying purposes and/or forheating thermally operated refrigerating machines.

Deviating from this, the KM2 may contain a liquid and/or gas phase whenreturning from the objects to be cooled to the heat exchanger, partialamounts of which may condense on the way. In this case, the liquid phasecollects at the bottom of the header due to gravity. The liquid phasecan be transported from the receiver to the liquid line or to the heatexchanger 2 by the following mechanisms without using a motor-drivencontrolled pump:

Drainage by capillary action with an appropriate mesh, evaporation withthermal energy, or with the aid of a bladder or venturi pump. Provisioncan be made to allow a column of liquid to form, which actuates a(float) valve and allows the liquid to drain into the liquid line.

It may be provided that liquid portions of the heated and partiallyvaporized KM2 are carried along by a collector line in which the gas isentrained and accelerated (by constriction of the line) in such a waythat it also entrains the liquid against the force of gravity.

A direct flow of the heated KM2 into the heat exchanger 2 can beprovided, which cools KM2 with KM1, so that no header is needed and theliquid fractions do not have to be transported against gravity. Inparticular, this can be realized by a shell-and-tube heat exchanger or acoil-and-tube heat exchanger, or by a plate heat exchanger in which theinflow of KM2 is distributed to the plate passages.

Computers, servers and IT equipment are being built smaller and smallerthese days. However, the heat generated in the CPUs/GPUs is not reducedto the same extent, but even increased in some cases. An enormouscost-saving potential on the part of data center operators is thepossibility of overclocking the servers. In this mode of operation, thecomputing power of the servers can be increased so that fewer servershave to be operated, but this also further increases the heat load perCPU/GPU. Therefore, cooling solutions must dissipate increasingly higherloads per area while also being compact. Active air cooling cannotachieve sufficient heat transfer coefficients as water-liquid cooling orrefrigerant evaporative cooling can. In addition, air heat exchangersrequire high heat transfer surfaces and additional fans, which increasesspace requirements, electrical power consumption, and noise. Whencooling with a conductive liquid such as water, there is a risk thatleaks could cause severe damage to servers, which is why many users donot prefer such cooling. Therefore, it makes sense to use a dielectricfluid for cooling. In addition to high air velocities through fans pastlarge heat-transferring surfaces, air cooling also requires largetemperature differences to dissipate heat. This temperature differencecan be reduced by refrigerant cooling because the heat transfercoefficient is so much greater. However, other components in servers andserver racks still need to be cooled with air because refrigerantcooling would be too costly and the heat loads per area are not asgreat. However, these components can also be cooled with warmer air(e.g. 40-50° C.) or designed for it, than the approx. 24 to 28° C.usually required for CPU/GPU air cooling.

Thus, the overall temperature level of the refrigeration can be greatlyincreased. The heat from the dielectric refrigerant 2 (KM2) and also theheat from the air can then be removed at a much higher temperaturelevel. This is done in air-to-water server cabinet air conditioners orair-to-refrigerant server cabinet air conditioners, which also condenseor cool the dielectric refrigerant (KM1) that cools the CPUs/GPUs withthe cooling water or refrigerant (generally KM2). All heat energy isthen supplied to KM1 in the device at a very high temperature level, sothat, for example, cooling water temperatures with a supply temperatureof 38° C. and a return temperature of 45° C. are achieved (approximatelyinstead of, for example, supply 18° C. and return 25° C.). At thistemperature level, the heat can be dissipated to the environment even insummer in many countries, and in winter it can also be used to heatbuildings or bathrooms or similar. The purchase of a chiller can thus beunnecessary for many applications.

A direct transfer of heat through the KM2 to the ambient air can also beprovided. However, special piping would have to be installed for thispurpose, since, for example, the dielectric refrigerants1,1,1,2,2,4,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone or1,1,1,2,3,3-heptafluoro-3-methoxypropane have small vapor densitiesrelative to other refrigerants and the evaporating temperature is verypressure sensitive relative to other refrigerants. Water or anotherrefrigerant with higher vapor density and lower pressure sensitivity ofevaporating temperature are therefore more suitable for transportingheat over a longer distance. By raising the temperature level in thesupplied air as well, heat from the cooling air can also be transferredto KM1 at this high temperature level. Since neither KM2 nor the coolingair now need to be cooled to less than 40-50° C., a chiller is often notneeded. By keeping this hot air in the cabinet, the working conditionsin the data center are more comfortable for the employees.

FIG. 21 illustrates the fluid routing of the embodiment according toFIG. 3. Accordingly, a closed air routing system is described in whichthe air is circulated exclusively between the switch cabinet housing 1and the cooling unit 2. In particular, no air supply is provided fromoutside the Switch cabinet arrangement. In contrast, cooled liquid, forexample cooled water provided by a chiller, is supplied to thearrangement from outside via a supply 5. Via a return 16, the heatedliquid is fed back to the recooler, for example to said chiller.

After leaving the air-liquid heat exchanger 3, the cooled air providedvia the air-liquid heat exchanger 3 is first fed in its flow directionto the components 4, which may be the components of a serverarrangement, for example. The air impinges on the server components 4,whereby a heat transfer from the components 4 to the air takes place,i.e. the air is heated. After the air has passed the components 4, it isfed back to the air-refrigerant heat exchanger 3 for recooling.

The cooled liquid provided via the supply line 5 is heated by the airpassing through the air-liquid heat exchanger 3 and is introduced via areturn line 6 of the heat exchanger 3 from the heat exchanger 3 as aheated liquid into a supply line 8 of a liquid-liquid heat exchanger 7.Via the liquid-liquid heat exchanger 7, a refrigerant circuit isrecooled, via which an at least proportionally liquid refrigerant is fedto components 4 in particular need of cooling, i.e. components whichhave a high heat flux density. These components 4 can be CPUs, forexample. For cooling the components, it may be sufficient that theliquid fed in this refrigerant circuit has a temperature that issubstantially higher than the air circulated in the switch cabinethousing 1. For example, the fluid may have a temperature of about 50° C.Since the return temperature of the air-liquid heat exchanger may be,for example, 35° C., this already partially heated liquid is stillsufficiently cool to provide re-cooling of the liquid for componentdirect cooling.

Accordingly, the liquid introduced from the heat exchanger 3 via theflow 8 into the heat exchanger 7 is further heated as it passes throughthe heat exchanger 7 and can be heated, for example, to 50° C., at whichtemperature the liquid then leaves the arrangement 1 again via thereturn 16, for example to be fed to a shill for renewed recooling andfeeding into the flow 5.

Deviating from the embodiment according to FIGS. 3 and 21, FIGS. 22 and23 show an embodiment in which the air in the arrangement is notcirculated, but is guided through the arrangement from a rear side ofthe arrangement and leaves the arrangement again at a front side of thearrangement. In this case, the air flow entering the arrangement via therear side is divided into a first partial flow and a second partialflow, the first partial flow acting on the cooling unit 2 and the secondpartial flow acting on the switch cabinet arrangement and, inparticular, on the components 4 accommodated therein, which do notrequire liquid cooling, in order to cool them.

A further air-liquid heat exchanger 18 is arranged in the cooling unit2, which is charged by the air passing through the cooling unit 2. Fans19 may be provided to drive the air through the heat exchanger 18 at anadjustable flow rate. The liquid circuit to which the liquid-air heatexchanger 18 is connected is designed for direct component liquidcooling, as already described in principle with reference to thepreceding embodiment.

Deviating from the previously described embodiments, no air-liquid heatexchanger for cooling the air with which, for example, the furtherair-liquid heat exchanger 18 and the components 4 are charged isprovided directly in the cooling unit 2 or the switch cabinet housing 1.Rather, this may be accommodated outside the arrangement, for example ina raised floor of a data center in which the switch cabinet arrangementis installed.

Another embodiment is shown in FIGS. 24 and 25. In this embodiment, itis again provided that air is passed through the switch cabinet housing1 for cooling components 4 accommodated in the IT rack or the switchcabinet housing 1. From the air passed through the housing, anair-liquid heat exchanger 18 is now further acted upon, wherein a liquidpassed through the air-liquid heat exchanger 18 is supplied to at leastone of the components 4 for heat transfer from the component 4 to theliquid and is discharged from the component 4 back into the air-liquidheat exchanger 18.

The air is thus again introduced into the switch cabinet housing 1 fromoutside the switch cabinet arrangement, for example via a rear sidethereof. Again, the air first passes through the components 4, wherebyin particular those components which do not have an excessively highheat flux density may already experience sufficient cooling. Afterleaving the components 4, for example after leaving a server housing inwhich the components 4 are accommodated, the air which is heated in theprocess passes through a liquid-air heat exchanger 18 which is nowaccommodated in a door 20 of the switch cabinet housing 1. Thedouble-walled door 20 further includes a fan 19 which draws air into theenclosure 1 via the rear of the enclosure 1 so that the air passesthrough the components 4, whereupon the air enters the door 20 andpasses through the heat exchanger 18. The heat exchanger 18 has a fluidtransition downstream to a passage through a front face of the enclosuredoor, through which the further heated air can exit the enclosure 1 ordoor 20. The passage may alternatively be formed, for example, at thetop of the door 20.

Optionally, but not necessarily, it may be provided that the heated airis supplied via a chimney 27 to a further air-liquid heat exchanger 26for recooling. The air leaving the housing 2 may, for example, have atemperature of 50° C., since, as has already been pointed out withreference to the previously described embodiments, it is heated to acorrespondingly high level due to the higher temperature level exhibitedby the liquid used for direct liquid cooling of the components 4.

FIGS. 26 and 27 describe an embodiment which is analogous to theembodiment according to FIGS. 3 and 21, with the cooling unit 2 nowbeing arranged in the door 20 instead of a side housing. In particular,the liquid-air heat exchanger 3 and the liquid-liquid heat exchanger 7fluidically connected thereto are both arranged in the door 20. Furtherdeviating from the embodiment according to FIGS. 3 and 21, it isprovided in this embodiment, analogously to the embodiment according toFIGS. 24 and 25, that the air is not circulated in a closed system, butenters the switch cabinet housing 1 via the rear side of the switchcabinet arrangement and exits the switch cabinet housing 1 again via thefront side of the switch cabinet housing, in particular via the door 20.

The further liquid-to-air heat exchanger 26 may be, for example, a heatexchanger disposed in a data center wall and separating, for example,the space of a data center from the environment of the data center orfrom another space in which a hot aisle or a hot aisle of the datacenter air conditioning system is provided.

The features of the invention disclosed in the foregoing description, inthe drawings as well as in the claims may be essential to therealization of the invention both individually and in any combination.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

1. A switch cabinet arrangement having at least one IT rack or switchcabinet housing and having at least one cooling device which has a firstair-liquid heat exchanger for cooling components accommodated in the ITrack or switch cabinet housing with cooled air, wherein the firstair-liquid heat exchanger comprises a first flow for cooled liquid and afirst return for heated liquid, characterized in that the cooling devicecomprises a liquid-liquid heat exchanger of a liquid cooling of thecomponents, to the second flow of which the first return of the firstair-liquid heat exchanger is connected, wherein a first of the twoliquids passed through the liquid-liquid heat exchanger has a boilingpoint under standard conditions that is below the boiling point of asecond of the two liquids passed through the liquid-liquid heatexchanger, and wherein the second liquid is the liquid passed throughthe first air-liquid heat exchanger.
 2. The switch cabinet arrangementof claim 1, wherein the first air-liquid heat exchanger is part of afirst cooling circuit and the liquid-liquid heat exchanger is part of asecond cooling circuit separate from the first cooling circuit.
 3. Theswitch cabinet arrangement of claim 1, wherein the liquid passed throughthe first air-liquid heat exchanger is water or a liquid comprisingmostly water.
 4. The switch cabinet arrangement according to claim 1,wherein the boiling point of the first liquid is at least 20 K, morepreferably at least 30 K, and most preferably at least 40 K below theboiling point of the second liquid.
 5. The switch cabinet arrangement ofclaim 4, wherein the first of the two liquids passed through theliquid-liquid heat exchanger is or comprises a perfluorinated chemicalcompound, preferably a compound derived from ethyl isopropyl ketone,more preferably perfluoro(2-methyl-3-pentanone), C₆F₁₂O.
 6. The switchcabinet arrangement of claim 4, wherein the first of the two liquidspassed through the liquid-liquid heat exchanger is introduced from athird return of the liquid-liquid heat exchanger into a liquid-carryingheat conducting body for conduction cooling.
 7. The switch cabinetarrangement of claim 6, wherein the first of the two liquids passedthrough the liquid-liquid heat exchanger is introduced from theliquid-carrying heat conducting body into a third flow of theliquid-liquid heat exchanger.
 8. The switch cabinet arrangementaccording to claim 1, wherein the liquid-liquid heat exchanger is thecooling zone of a heat pipe or a manifold.
 9. The switch cabinetarrangement of claim 8, wherein the heat pipe or the manifold comprisesa down pipe and a riser pipe, which are formed as fluidically separatedvertical pipes or are fluidically connected to each other in a lowermostregion of the heat pipe via a siphon.
 10. The switch cabinet arrangementof claim 8, wherein the heat pipe includes a down pipe into which firstliquid cooled from the liquid-to-liquid heat exchanger is introduced.11. The switch cabinet arrangement of claim 8, wherein the heat pipecomprises a riser pipe into which heated first liquid is introduced. 12.The switch cabinet arrangement according to claim 1, wherein liquidcooled by a recooler, for example a chiller, is introduced into theair-liquid heat exchanger via the first flow for cooled liquid.
 13. Theswitch cabinet arrangement of claim 12, wherein the cooled liquid isintroduced into the recooler as a heated liquid from theliquid-to-liquid heat exchanger.
 14. The switch cabinet arrangementaccording to claim 1, wherein the cooling device is a cooling devicearranged in a row of IT racks or switch cabinet housings, via the rearside or front side of which hot air is drawn in from a hot aisle andblown out as cooled air into a cold aisle via the side opposite the rearside or front side.
 15. The switch cabinet arrangement according toclaim 1, wherein the air-liquid heat exchanger of the first circuit andthe liquid-liquid heat exchanger of the second circuit are accommodatedin a rear or front door of the IT rack or the switch cabinet housing,wherein the air-liquid heat exchanger and the liquid-liquid heatexchanger have air flowing through them, which enters the IT rack or theswitch cabinet housing on a side arranged opposite the rear or frontdoor.
 16. The switch cabinet arrangement having at least one IT rack orswitch cabinet housing through which air is passed for coolingcomponents accommodated in the IT rack or switch cabinet housing,wherein a second air-liquid heat exchanger of a second cooling circuitis charged by the air and a liquid passed through the second air-liquidheat exchanger is fed to at least one of the components for heattransfer from the component to the liquid and is discharged from thecomponent back into the second air-liquid heat exchanger.
 17. The switchcabinet arrangement of claim 16, wherein the air from outside the switchcabinet arrangement is introduced partially into the at least one ITrack or the switch cabinet housing and partially into a cooling unithousing associated with and fluidically separated from the IT rack orthe switch cabinet housing, in which the second air-liquid heatexchanger is received.
 18. The switch cabinet arrangement according toclaim 16, wherein the air is introduced from outside the switch cabinetarrangement into the at least one IT rack or the switch cabinet housing,the switch cabinet arrangement comprising an air duct in which the airin its flow direction after entering the IT rack or the switch cabinethousing impinges on the components before it impinges on the secondair-liquid heat exchanger as air partially heated by the components. 19.The switch cabinet arrangement according to claim 17, wherein the secondair-liquid heat exchanger of the second circuit is arranged in a rear orfront door of the IT rack or the switch cabinet housing, the secondair-liquid heat exchanger having air flowing therethrough which entersthe IT rack or the switch cabinet housing at a side opposite to the reardoor or the front door.
 20. The switch cabinet arrangement according toclaim 19, wherein the IT rack or enclosure comprises an air duct inwhich the air in its direction of flow after entering the IT rack orenclosure impinges on the components before entering the rear door orfront door as air partially heated by the components and impinges on thesecond air-liquid heat exchanger of the second circuit.
 21. A method forair conditioning a switch cabinet arrangement, comprising: Chargingcomponents accommodated in an IT rack or a Switch cabinet housing of theswitch cabinet arrangement to air, whereby the air is heated to a firsttemperature, Passing the air heated to the first temperature through asecond air-liquid heat exchanger, wherein a liquid of a liquid coolingof the components is cooled and the air is heated to a secondtemperature greater than the first temperature.
 22. The method of claim21, wherein the air, after passing through the second air-liquid heatexchanger is discharged at the second temperature to the environment ofthe enclosure assembly or cooled by a further heat exchanger andrecirculated for re-impingement of air to the components.
 23. A methodfor air conditioning a switch cabinet arrangement, comprising:Subjecting components accommodated in an IT rack or a Switch cabinethousing of the switch cabinet arrangement to air, whereby the air isheated, Passing the heated air through a first air-liquid heatexchanger, cooling the air and heating a second liquid passed throughthe first air-liquid heat exchanger, Passing the heated second liquidthrough a liquid-liquid heat exchanger, wherein a first liquid passedthrough the liquid-liquid heat exchanger of a liquid cooling of thecomponents having a boiling point lower than the boiling point of thesecond liquid under standard conditions is cooled and the first heatedliquid is further heated.
 24. The method of claim 23, wherein the firstfurther heated liquid is diverted from the liquid-liquid heat exchanger,cooled outside the enclosure assembly, and recirculated as cooled liquidinto the first air-liquid heat exchanger.